It's vague because I didn't want 15 different options. Look at it like this.
No can mean that you believe it was mostly done by radical Muslims but there was major failures on our governments part that they covered up, or Maybe some part of our government may have actually helped. Or that maybe some other organization or country was involved that we don't know about, or the Saudis, Iran..
No can mean a lot of things.
Yes means that you believe Al-Qaeda acted alone directed by Osama, and there's no way our government, or anyone in it, or any other government had any involvement. And that for the most part the US Government has been honest about their findings. Building 7 collapsed because of office furniture fires, Osama was really killed and dumped in the ocean, the Pentagon missing 2.3 TRILLION dollars prior to the attack is a coincidence, and so on.
Well then I will reluctantly change my answer to no. Still a ****ty black and white poll, but not surprising you would want that.